The present invention relates to an image evaluation method, an image capturing method and a digital camera system thereof, and more particularly, to an image evaluation method for analyzing the composition of an image and generating a grade displayed to a photographer accordingly.
With the progress of semiconductor and image processing technologies, in recent year, digital still/video cameras have become popular and are often incorporated into portable devices, such as mobile phones and personal digital assistants. Digital cameras are developed toward higher resolution, powerful image processing capability, and user-friendly control interface. For example, a digital camera has different scene modes, such as portrait, landscape, night scene, etc., and captures a picture with a predetermined parameter setting of a chosen mode. The predetermine parameter setting is used to adjust parameters of the digital camera such as shutter speed and aperture to suit the chosen mode. Benefited from these advancements, people use digital still/video cameras more conveniently and take a photograph that meets basic image quality.
However, an image with low noise and high resolution does not intend that it is a good image if the composition of the image is bad. The image composition is a key to an interesting image, which concerns about the proportion of a main object to the entire image, relative sizes of objects, positions of the objects, and many other factors. For an ordinary photographer who is not skilled in photography, it is difficult to arrange objects in an impressive composition; at the same time, the photographer usually changes the zooming parameter and camera location at random before the image is actually captured, which is also called a “preview mode”. As a result, the composition of the captured image is typically not very impressive.